Progress in Research of Chitosan Chemical Modification Technologies and Their Applications

Abstract

Chitosan, which is derived from chitin, is the only known natural alkaline cationic polymer. Chitosan is a biological material that can significantly improve the living standard of the country. It has excellent properties such as good biodegradability, biocompatibility, and cell affinity, and has excellent biological activities such as antibacterial, antioxidant, and hemostasis. In recent years, the demand has increased significantly in many fields and has huge application potential. Due to the poor water solubility of chitosan, its wide application is limited. However, chemical modification of the chitosan matrix structure can improve its solubility and biological activity, thereby expanding its application range. The review covers the period from 1996 to 2022 and was elaborated by searching Google Scholar, PubMed, Elsevier, ACS publications, MDPI, Web of Science, Springer, and other databases. The various chemical modification methods of chitosan and its main activities and application research progress were reviewed. In general, the modification of chitosan and the application of its derivatives have had great progress, such as various reactions, optimization of conditions, new synthetic routes, and synthesis of various novel multifunctional chitosan derivatives. The chemical properties of modified chitosan are usually better than those of unmodified chitosan, so chitosan derivatives have been widely used and have more promising prospects. This paper aims to explore the latest progress in chitosan chemical modification technologies and analyze the application of chitosan and its derivatives in various fields, including pharmaceuticals and textiles, thus providing a basis for further development and utilization of chitosan.

Keywords: alkaline cationic polymer; chemical modification; chitosan; chitosan derivatives.

Figure 4

CS esterification modification scheme: (A) Synthesis route of sulfated chitosan. Adapted with permission from [66], Copyright © 2021 Elsevier. (B) synthesis route of phosphorylated chitosan. Adapted with permission from [65], Copyright © 2019 Elsevier.

Figure 6

CS quaternary ammonium salt modification scheme: (A) The synthetic route of N-quaternary ammonium salt. Adapted with permission from [75], Copyright © 2012 Elsevier. (B) the synthetic route of O-quaternary ammonium salt. Adapted with permission from [80], Copyright © 2016 Elsevier.

Figure 1

Carboxylation modification reaction scheme of chitosan: (A) Synthetic route of O-carboxymethylated chitosan. Adapted with permission from Ref. [34]. Copyright 2020 Elsevier. (B) synthetic route of lysozyme-N-succinyl chitosan. Adapted with permission from Ref. [36]. Copyright 2020 Elsevier.

Figure 2

The reaction scheme of chitosan alkylation modification. The synthetic route of N,N-CTS [39].

Figure 3

Modification scheme of N-acylated chitosan: (A) The synthetic route of O-acylated CSNFs. Adapted with permission from Ref. [50]. Copyright 2017 Elsevier. (B) the synthetic route of NSC and its structural characterization. Adapted with permission from Ref. [51]. Copyright 2016, Elsevier.

Figure 5

CS sulfonation modification scheme. Adapted with permission from Ref. [68]. Copyright 2019 Elsevier.

Figure 7

APANCS synthetic route [84].

Figure 8

CS Schiff base modification scheme. Adapted with permission from Ref. [87]. Copyright 2016 Elsevier.

Figure 9

Effects of CMCS on histopathology and CD34 expression in H22 tumor tissue. (A) Effect of the CMCS on histopathology of H22 tumor tissue was recorded by the light microscope. (B) Photographs of effect on CD34 expression of H22 tumor tissue were taken by the light microscope. (C) Inhibition rate of CMCS on CD34 expression of H22 tumor tissue, * p < 0.05, ** p < 0.01 significant difference compared with control group. Adapted with permission from Ref. [102]. Copyright 2015 Elsevier.

Figure 10

Preparation of composite sponge and its hemostatic test result. (A) The photo of the composite sponge with blood; (B–F) The SEM images of blood cells adhesion of the CS, Hydroxybutyl chitosan (HBC), HC-1 (M_CS:M_HBC = 1:3), HC-2 (M_CS:M_HBC = 1:2) and HC-3 (M_CS:M_HBC = 1:1) respectively. Adapted with permission from Ref. [109]. Copyright 2018 Elsevier.

Figure 11

Preparation method of QCS and DQCS and test results of antioxidant activity. (a) Synthetic route for the preparation of QCS and DQCS; (b) Antioxidant effect of samples [114].